An example of creating an EntityProvider that provides a RESTful api to some resource in Sakai. This assumes you have an environment set up for sakai development. This specific example is for version 10.3 of Sakai, modify the base pom.xml to compile for other versions.
cd into your sakai source directory
git clone https://github.com/cschauer/sakai-example-entityprovider sakai-example-entityprovider
cd sakai-example-entityprovider
mvn clean install sakai:deploy -Dmaven.tomcat.home=/path/to/your/tomcat
Restart tomcat and you should see example-entityprovider listed at /direct/describe.